Circuit breaker



GS, `949- J. M. CUMMING ET AL CIRCUIT BREAKER 2 Sheets-Sheet l Filed July 9, 1946 ugl@ 1949 l J. M. @UMA/:ING ET Ax. @9479?32@ CIRCUIT BREAKER v Filed July 9, 1946 l 2 Sheets-Sheet 2 ATTORNEY lock nut 13. The adjusting screw 1| is disposedV Y nected to a trip lever 11 pivotally mounted on a pivot pin 19. The pivot pin 19 is supported by and extends between a pair of spaced brackets 8| (only one being shown) rigidly mounted on the underside of the projection 5| of the main casting The trip lever 11, at its pivoted end, is provided with a pair of projections 83 (only one being shown), one disposed on each side of the 'lever 11 and rigidly secured thereto. The projections 83 are mounted on the pivot pin 19 to pivotally support the trip lever 11 thereon.

The trip rod 15 is biased in tripping direction by means of a stored-energy device comprising a relatively strong tripping spring 95 Which is compressed between the tripping lever 11 and a support lever 81. The support lever 81 comprises a pair of spaced parallel levers having an arm 89 rigidly secured between them at their right-hand ends for -pivotally supporting the lever 81 on the Y pivot pin 19.

A rod 9| pivotally connected by means of a pin Y 93 to the lever 81 projects upwardly through an opening in the trip lever 11; A washer 95 surrounding the rod 9| above the trip lever and a pin 91 in the rod 9| provide a lost motion connection between the lever 11 and the lever 81. A spring guide 99 surrounds the rod 9| within the coil of the tripping spring 85.

The force of the tripping spring 85 biases the trip lever 11 in clockwise or tripping direction about the pivot pin 19, and biases the lever 81 in a counterclockwise direction about the pin 19. The lever 81 in the closed position of the breaker is restrained by the levers 23 in the position shown in Fig. 1, in order to maintain the spring 85 in compression and in readiness to trip'the breaker. The free end of the lever 81 is connected by means of an adjustable .connecting rod to a lever |03 pivoted on the pivot `pin 43 on which the main latch 4| is mounted. The right-hand end of the lever |03 is rounded and is engaged and held in the position shown by a cross member |05 rigidly connecting the parallel operating levers 23. The tripping lever 11 is normally restrained against tripping movement by means of a lightported in the brackets 8| A horizontally extending tail of the latch |09 is disposed above a trip rod ||3 secured to the armature ||4 of a low energy tripping electromagnet illustrated 4 rent or by operation of a manual switch, the trip rod |13 is actuated upwardly and operates the latch |01 to release the trip lever 11. The trip lever 11 is immediately operated by the tripping spring 85 and moves the trip rod 15 upwardly to strike the tail 59 a hammer blow and operate the auxiliary latch 59. Operation of the auxiliary latch 59 frees the main latch 4| and permits the accelerating spring 5 to move the main latch vout of the way of the latch roller 31 and to move the breaker mechanism to the open position.

The tripping movement of the trip lever 11 is limited by the Washer 95 striking the pin 91 which also neutralizes the force of the spring 85. Movement of the operating lever 23 to the open position permits the lever |03 and the support lever 81 which supports the stored-energy device to rotate in a counterclockwise direction about their respective pivots. This movement is aided by means of a spring |2I surrounding the trip rod 15 and `compressed between a shoulder on the trip rod and a spring seat in the projection 5| of the casting il. The counterclockwise movement of the lever 81 acting through the rod 9| and pin 91 and assisted by the spring |21 resets the tripping lever 11 to its latched position.

As soon as the latch roller 31 is clear of the main latch 4|, this latch is immediately restored to its latching position by the spring 41. If, in this position of the main latch 4|, the auxiliary latch 59 were permitted to resume its latching position under the tail 61 'of the main latch, it would be impossible for the latch roller 31, upon closure of the breaker, to resume its latching position relative to the main latch 4|. It is, therefore, necessary to prevent movement of the auxiliary latch 59 to its latching position until after the breaker is closed and the main latch is properly engaged with the roller 31. To this end, a holding lever |23 pivoted on the pivot pin 8| is provided. The holding lever 23 is provided with a cross member |25 integral therewith and is biased by means of a spring |21 in a direction to engage the cross member |25 with the tail 69 of the auxiliary latch. The holding lever |23, in the closed position of the breaker, is prevented from engaging the auxiliary latch by engagement of the roller 31 with a cross member |29 integral with the holding lever |123.

When the operating levers 23 move in opening direction, following a tripping operation of the trip mechanism, the spring |21 moves the holding lever |23 clockwise about the pivot 5| to engage the cross member |25 with the tail 89 of the auxiliary latch 59 and holds the latch in un- Y latching position until the breaker is closed.

,load latch |01 Vpivoted on a pivot pin |09 supgenerally at |5, The armature ||4 in the un- The piston |1 and the breaker mechanism is operated to closed position by admitting compressed gas to the cylinder I3 above the piston I1, which, when the breaker moved to open position, assumed a position in the upper end of the cylinder. Compressed gas is admitted through an inlet passage |34 tothe cylinder by means of an electromagnetically operated inlet valve device indicated generally at |33. The inlet valve device comprises an inlet valve |35 and an exhaust valve |31 both mounted on a valve rod |39. The inlet valve |35 is biased closed and the exhaust valve |31 is biased to open position by means of a spring |4I. The rod |39 is secured to an armature |53 of an electromagnet indicated generally at |45 which, when energized in a wellknown manner, moves the armature |43 downwardly to open the inlet valve |35 and close the exhaust valve |31 thus admitting compressed gas f5 to the cylinder to move the piston |1 downwardly to close the breaker.

As the breaker nea-rs the closed position, the latch roller 31 vengages the beveled end or the main latch 4|, and, since the auxiliary 'latch is held in unlatching position, moves the main latch A4| in unlatching direction. As soon as the roller 31 clears the nose of the main latch 4|., the spring 41 Arestores this latch to latching position. As the roller 31 vmoves to its latchng position, it .engages the cross m'ember |29 Aand moves the hold- `ing lever |23 to free the auxiliary latch 5.9 which is then moved by its spring 65 to latching engagement with the main latch.

As the operating levers 23 approach the closed position, the .cross bar |95 engages the end ofthe lever |53 rocks this lever in clockwise :direction. During this movement, the lever |03, acting through the rod |51, raises the stored-energy device support .lever 2.1, Iand, since the tripping `lever 11 is now Arestrained by the latch |91, compresses the .stored-.energy means or tripping spring in preparation for another tripping operation.

'The modification .of the trip mechanism shown in Fig. 2 of the drawings is shown applied to a. circuit breaker of the same type as that shown in Fig. 1. Consequently like reference numerals 'have vbeen applied to like parts. The trip mechanism is indicated generally at |5| (Fig. 2) vand comprises a trip rod |53 having its upper end disposed beneath the tail B9 of the auxiliary latch 59 and its lower end pivotally connected to a heating `trip lever |55 by means of a Apivot pin |51.. by means of a light-load latch |59 against the bias of stored-energy device or tripping spring |6|. The latch |59 'is pivoted on a pin |53 supported in the sides of a U-shaped bracket |65 secured to the projection 5| of the main casting 153|' and is lbiased to .latc'hing position by means o'f a spring |51. The other end ofthe tripping lever |55 is restrained against movement in tripping direction by mea-ns of a restoring rod |69 the lower end of which bears against the floating lever |55 and the upper end of the rod |59 bears against and is restrained against upward movement by the cross member |25 of the holding lever |23.

The tripping spring |61 is compressed vbetween a spring guide |1|` pivotally connected to the iioating trip lever |55 by a pin |13, andthe yoke y7.45 of the U-shaped bracket |65. A spring |11 surround-ing the upper end of the -rod |69 and compressed between the cross member |25 vof the holding lever |123 and a spring seat in the vpro- `jection 5| of the main casting |l biases the holding'lever |23 to its operated position.

When the trip magnet ||5 fis energized, the armature H4 thrusts lthe trip rod ||3 upwardly, striking a tail |19 on the light-load latch |59 and operating the latch to release the left hand end of the floating trip lever |55. Release vof the trip lever |55 permits the tripping spring |f6| to expand. rocking the trip lever '|55 in clockwise or tripping direction about its point of engagement with the rod 59 Aas a fulcrum. This operation of the trip lever thrusts the trip rod |53 upwardly to strike the tail V5|! of the auXi-liary latch a hammer blow and operatethe auxiliary latch '159. The

tripping movement of the trip rod |53 is Vlimited bv the engagement of a shoulder |-8l thereon h the projection 5| of the main casting. Operationv of the auxiliary latch 59 releases the main latch 4| 'and permits opening yof ythe breaker in @ne end of the trip lever |55 is restrained i the previously described manner.V As the roller 31 moves in opening direction, the spring |'11zrotates the holding lever |23 to engage the cross member |25 with the tail 69 of the auxiliary latch 59 and hold this latch in unlatched position. Movement of `the holding lever |23 ,and its cross member |25 vpermits the tripping spring 16| to expand farther and rock the oating tripping lever H55 counterclockwise about the pin |51 which is, at this time, held against movement by engagement of the .shoulder |8| with the projection 5|. This causes the latching end of the trip lever to reengage the latch |59.

The breaker mechanism is operated to closed f circuit position by energization of the closin electromagnet |45 which operates the inlet valve mechanism l 33 and admits compressed gas to the cylinder i3 in the manner previously described. As the breaker mechanism moves to closed .position and the roller 31 approaches the latched position, it engages the cross member |29 of the holding lever |23 and opera-tes `this lever in a counterclockwise direction to release the auxiliary latch for the purpose set forth previously. Movement or the :holding lever |23 in counterclockwise direction causes .the cross member |25 to move the rod |69 downwardly `rocking the iloating trip lever |55 clockwise about Aits poi-nt of engagement with the latch |59. This compresses Ythe tripping spring 16| Ito store energy therein in preparation for a subsequent tripping operation and, at the same time, moves the trip rod |53 downwardly to permit relatch'ing of 'the auxiliary latch 59 with the main latch 4| rto releasably restrain the circuit breaker in the closed position.

From the foregoing, it will be seen that there 'is provided a light-load, high-speed latchlng mechanism for controlling the tripping of a circuit breaker, the latch mechanism being operated by stored energy released by a light-load latch actuated by the energ-ization of an electromagnet which requires a minimum of energy.

While the invention has been disclosed iin ace cordance with the provisions of the patent statutes, it is to be understood that various changes in the structural details and arrangement of parts thereof ymay be made without departing from some `of the essential features of the invention.

We claim as our invention:

1. In a circuit breaker including operating mechanism therefor, latching mechanism ior releasably restraining said operating mechanism in closed position comprising a main latch, an auxiliary latch for restraining said main latch in latching position and operable to release said main latch, stored energy means for operating said auxiliary latch, means comprising alightload latch releasably restraining said stored energy means, trip means comprising low energy electro-responsive means responsive to A4overload currents for operating said light-load latch to release said stored energy means, and a member F automatically operated by said vbreaker operating mechanism during a closing operation to store energy in said stored energy means.

2. In a circuit breaker including operating mechanism therefor, latching mechanism for releasably restraining said operating mechanism in closed position comprising a main latch, ,an auxiliary latch for restraining said vlatch in latching ,position and operable to release said main latch, stored energy means for operating said auxiliary latch, means comprising alightload latchV vreleasably restraining said stored energy means, and trip means comprising low energy electro-responsive means for operating said light-load latch to release said stored energy means, a support member for movably supporting said stored energy means, and a part movable with said operating mechanism upon opening of said breaker to permit movement of said support member to effect relatching of said stored energy means.

3. In a circuit breaker including operating means therefor, latching mechanism for releasably restraining said operating means in closed position comprising a main latch biased to latching position, an auxiliary latch biased to latching position for releasably restraining said main latch in latching position, a trip lever operable to operate said auxiliary latch to effect release of said operating means, stored energy means for operating said trip lever, means comprising a light-load latch for releasably restraining said trip lever against tripping operation, and a trip device comprising electro-responsive means for operating said light-load latch to release said trip lever, and resetting means operated by said operating means to rst elect relatching of said trip lever and then to store energy in said storedenergy means.

4. In a circuit breaker comprising operating means therefor, latching mechanism for releasably restraining said operating means in closed 'position comprising a main latch biased to -ing said stored energy means and movable upon movement of said operating means in opening direction to permit relatching of said trip lever.

5. In a circuit breaker comprising operating means therefor, latching mechanism for releasably restraining said operating means in closed position -comprising a main latch biased to latching position, an auxiliary latch biased to latching position for releasably restraining said main latch in latching position, a trip lever operable to operate said auxiliary latch to effect release for operating said trip lever, means comprising a light-load latch for releasably restraining said trip lever against tripping operation, and a trip device comprising electro-responsive means for operating said light-load latch to release said trip lever, and movable support means supporting said stored energy means and operable upon movement of said operating means in opening direction to .permit automatic relatcliing of Vsaid trip lever, and means actuated by said operating means during a closing movement thereof for actuating said movable support to store energy in said stored energy means.

6. In a circuit breaker comprising power operated operating means for closing said breaker, latching mechanism comprising a main latch for engaging a part movable With said operating means to releasably restrain said operating means in closed position, an auxiliary latch for restraining said main latch in latching position and operable to release said main latch, storedenergy means for operating said auxiliary latch, means comprising a light-load'latch for releasably restraining said stored-energy, electro-responsive means operable to actuate said lightload latch to release said stored-energy means to effect operation of said latch mechanism and release of said operating means, resetting means operable upon movement of said operating means in opening direction to reset said stored energy restraining means, and a member on said operating means for engaging and actuating said resetting means to store energy in said stored energy means.

7. In a circuit breaker comprising operating means therefor, latching mechanism for releasably restraining said operating means in closed position comprising a main latch, an auxiliary latch for restraining said main latch in latching position and operable to release said main latch, holding means operable upon movement of said operating means in opening direction to maintain said auxiliary latch in non-latching position, means comprising a stored-energy device for operating said auxiliary latch, latch means for restraining said stored-energy device against operation, electro-responsive means operable when energized to release said stored-energy device to elTect opening of the breaker, and means operable by said holding means when said operating means moves to closed position to store energy in said stored-energy device.

8. In a circuit breaker comprising operating means therefor, latching mechanism comprising a main latch for releasably restraining said operating means and an auxiliary latch for restraining said main latch in latching position, a trip member for actuating said auxiliary latch to release said main latch, holding means for restraining said auxiliary latch in non-latching position when the operating means isrin open position, energy storing means operable when released to operate said trip member, electro-responsive means operable to release said energy storing means to elect opening of the breaker, and means operable by said holding means during a closing operation of said operating means for storing energy in said energy storing device.

9. In a circuit breaker, including operating means therefor, latch means for releasably restraining said operating means in closed position, means comprising a floating lever operable to actuate said latch means to effect opening of said breaker, energy storing means biasing said iloating lever in a direction to actuate said latch means, holding means operated by the operating means in the closed position to restrain one end of said lloating lever, a light-load latch normally restraining the other end of said floating lever, electro-responsive means for operating said lightload latch to release said oating lever to thereby permit said energy storing means to actuate said lever, said energy storing means acting to reengage said floating lever with said light-load latch during opening movement of said operating means, and means operated by said holding means during closing movement of said operating means to store energy in said energy storing means.

10. In a circuit breaker including operating mechanism therefor, latching mechanism comprising a main latch for releasably restraining said operating mechanism in closed position and an auxiliary latch for releasably restraining said main latch in latching position, a floating lever operable to actuate said auxiliary latch, energy storing means biasing said oating lever in trip- 9 ping direction, a light-load latch for releasably restraining said floating levei` against tripping operation, and electro-responsive means for operating said light-load latch to release said floating lever.

11. In a circuit breaker including operating mechanism therefor, latching mechanism comprising a main latch for releasably restraining said operating mechanism in closed position and an auxiliary latch for releasably restraining said main latch in latching position, a floating lever operable to actuate said auxiliary latch, energy storing means biasing said iloating level` in tripping direction, a light-load latch for releasably restraining said floating lever against tripping operation, electro-responsive means for operating said light-load latch to release said iloating lever, and means operable upon movement of said operating mechanism to open position to permit said energy storing means to relatch said floating lever.

12. In a circuit breaker including operating mechanism therefor, latching mechanism comprising a main latch for releasably restraining said operating mechanism in closed position and an auxiliary latch for releasably restraining said main latch in latching position, a iloating lever operable to actuate said auxiliary latch, energy storing means biasing said floating lever in tripping direction, a light-load latch for releasably restraining said floating lever against tripping operation, electro-responsive means for operating said light-load latch to release said floating lever, and means operable upon movement of said operating mechanism to open position to permit said energy-storing means to relatch said iioating lever, said means being operable upon closing movement of said operating mechanism to store energy in said energy storing means.

JAMES M. CUMMING.

DAVID C. BLEWITT.

REFERENCES CITED The following references are of record in the ie of this patent:

UNITED STATES PATENTS Number Name Date 552,954 Chute Jan. 14, 1896 1,271,964 WaldoW July 9, 1918 2,372,140 Van Sickle Mar. 20, 1945 

